Important Notice

The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

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'This example uses the OUT statement and the INP function to control
'the timer and speaker to produce a note.
 
'Play a scale using speaker and timer.
CONST WHOLE = 5000!, QRTR = WHOLE / 4!
CONST C = 523!, D = 587.33, E = 659.26, F = 698.46, G = 783.99, A = 880!
CONST B = 987.77, C1 = 1046.5
CALL Sounds(C, QRTR): CALL Sounds(D, QRTR)
CALL Sounds(E, QRTR): CALL Sounds(F, QRTR)
CALL Sounds(G, QRTR): CALL Sounds(A, QRTR)
CALL Sounds(B, QRTR): CALL Sounds(C1, WHOLE)
 
SUB Sounds (Freq!, Length!) STATIC
'Ports 66, 67, and 97 control timer and speaker.
'Divide clock frequency by sound frequency
'to get number of "clicks" clock must produce.
    Clicks% = CINT(1193280! / Freq!)
    LoByte% = Clicks% AND &HFF
    HiByte% = Clicks% \ 256
'Tell timer that data is coming.
    OUT 67, 182
'Send count to timer.
    OUT 66, LoByte%
    OUT 66, HiByte%
'Turn speaker on by setting bits 0 and 1 of PPI chip.
    SpkrOn% = INP(97) OR &H3
    OUT 97, SpkrOn%
'Leave speaker on.
    FOR I! = 1 TO Length!: NEXT I!
'Turn speaker off.
    SpkrOff% = INP(97) AND &HFC
    OUT 97, SpkrOff%
END SUB